A deal brokered by Russia, Turkey and Iran this month has stopped much of the violence in Idlib province and three other regions of Syria. But if the truces break down and fighting resumes, the stakes will be highest in the northwest: The Turkish border is tightly controlled, and pro-government forces have been closing in for months. Across the province, a coalition of al-Qaeda-linked rebels would be firmly in Assad’s crosshairs, with hundreds of thousands of civilians stuck in the middle.

From his tent in a packed displacement camp along the Turkish border in the days before the deal, Qassim Qadoor called his children close as a drone hovered overhead. When it dropped its payload, he said, they ran for cover, passing the flames that savaged their neatly stacked possessions and destroyed the latest refuge for dozens of families just like them.

“We came here because there was nowhere left to go,” Qadoor said in a phone interview after the attack. His family had been uprooted nine times since the start of Syria’s conflict before arriving at the camp.

“The borders are closed, the regime is coming,” Qadoor said.